Brake mechanism



June 17, 1941. Q c, FARMER BRAKE MECHAN'ISM' Filed Feb. 29, 194olNvENTo'R CLYDE C. FARMER BY Mug ATTORNEY Patented June 17, 1941 MECEHANISM Clyde C. Farmer, Pittsburgh, Pa.,passignorto,'1flie WestinghouseAir Brake Cnmreny, Wilmerdine. Pa., a corporation of Pennsylvania Application February 29, 1940, Ser-alfNo. '321,466

(Cl. 18S-203). v

8 Claims.

lThis inventionk 'relatesl to slack adjusters for uid pressure brakes, and more particularly to a slack` adjuster of, the type which is automatically operative to take up slack in the brake. rigging in response to movement of the 'usual brake cylinderl piston beyond a predetermined range.

Recent developments in the designing of rail- Way trucks `have involved the mounting of air brake cylinders and associated brake devices on the truck frame, Where space available lor accessory devicesv isv necessarily limited.v One .of the Vbrake accessory .devices which has been found dileult to, confine within space available on such, a. truck is the slackv adjuster,y which is required, for adjusting the.. brake rigging to eempenSate for wear.

. It is the principal object of my invention to provide .a slack adjuster mechanism constructed .and arranged for operation by a brake cylinder .device having a casing structure adapted to have mounted thereinV (both, the usual brake cylinder 'piston and the operating elements of the slack adjuster apparatus.

Another object of the invention is to provide a brake cylindel. device including a casing structure adapted to inclose an improved slack adjuster mechanism which is operative in accordance with travel of the brake cylinder piston to adjust elements of the brake rigging associated with the` brake cylinder device.

Other objects and advantages of the invention will be apparent in the following more detailed description thereof, taken in conjunction with the accompanying drawing, in which Fig. 1 is a plan view', mainly in section, of, a brake. cylinder and slack adjuster apparatus constructed in accordance with my invention;

and

Fig. 2 is a fragmentary sectional view taken substantially along the line 2 -,2 of Fig. 1.

As shown in Fig. 1 of the drawing, a casing structure ist provided for the combined brake cylinder and slack adjuster apparatus and includes a cylinder section l0, an intermediate section II and an end section I2, which casing sections are clamped together fby suitable means, such as bolts, not shown. The cylinder section I0 of the casing Structure has formed therein a borel4 in which is slldably mounted a piston I5 which is subject at its. outer side to the pres,- sure of fluid supplied in the usual manner to a chamber I6 through the medium of a suitable pipe, not shown. Interposed between the piston I5 .and an annular shoulder I'I formed on the inner wall of the casing section II is a coil spring I9, which normally maintains the piston in brake release position as show-n lin the drawing. Secured tothe piston I5 is a 'tubular member 2l! `which extends longitudinally through the casing structure and is s'l-idably mounted in a bore v2I formedin .the Len d section I2 of the casing structure, and which 'is' adapted to receive the 'usual piston rod 2-2.

The outer end of the piston rodV 22 is pivotally connected 'by means of apin 24 to one end of a floating or live brake lever l25, the opposite end `of which is operatively connectedvthrough the medium of a pin 2- Ii and 'pull rod 21 with .the

usual brake rigging elements, not shown.'

lFormed on the cylinder section lil of the l'casing structure is a lug 28, 'which carries a pin 28 that is pivotally connected to one` end of a dead brake lever 30. The other en d of the lever 30 is kpivotally vconnected by means 'of a pin 3I to a pull rod 32, which is connected in the usual mannen to other members Yof the brake rigging.

According to the invention, avsleeve element 35 is slidably mountedon the tubular member 20, and' vis provided suitable means' not shown.,r for preventingA rotary movement of the sleeve member while Vpermitting longitudinal movement thereof relatively to the tubular member. The sleeve member 35 has an enlarged portion 36 on which is formed an annular surface 31 that is adapted to'engage the annular shoulder I'I of the casing section AII for limiting inward movement of the sleeve member. A coil spring 3,9 is interposed between the end of the enlarged portion 36 of the sleeve member and an annular shoulder 40 formed on the outer end o f the casing section I2, and is adapted to resistA movement of the sleeve member during operation thereof by the brake cylinder piston I5, which is provided with a collar portion 42 engageable with the inner end of the sleeve member.

The sleeve member 35 is constructed and arranged to operate a ratchet and gear mechanism comprising a transversely 'disposed rotary shaft 4,5, which is suitabltf journaled in the casing structure and has; secured thereto a ratchet wheel 46. A drive pawl 48 is pivotally mounted on the enlarged portion 3B of the sleeve member 35 by means of a pin 49, and is arranged to rest in interlocking engagement with the teeth of the ratchet wheel 46. If desired, suitable spring means, not shown, maybe provided for biasing the drive pawl 48 toward. its engaged position, it being noted .that the paw] is constructed and arranged to ride over the ratchet wheel during movement of the sleeve member to the left, as viewed in Fig. 1.

For preventing counterclockwise rotation of the shaft and ratchet wheel 46 there is provided a stop pawl 5|, which is pivotally mounted on a pin 52 carried by the casing struicture and is urged into engagement with the teeth of the ratchet Wheel under the force of a coil spring 53 that is interposed between a lug 54 formed on the pawl and a recessed wall 55 formed o the casing section I2.

Formed on the rotary shaft 45 is a worm gear portion 56, which is operatively intermeshed with a similar worm gear portion 51 of a shaft 58, which is preferably disposed longitudinally of the brake cylinder casing structure and has a bearing portion 59 journaled in the casing sec-V As shown in the drawing, the shaft 58V `are operatively mounted on the screw member60,

the block member havingY a suitably threaded bore for engaging the screw portion 6| and the block member 66 having an oppositelythreaded bore iitting the screw portion 62. The adjusting block element 65 is voperatively connectedV to a pair of spacing levers 58, which, as best shown in Fig. 2 of the drawing, are providedwith suitable "apertures for receiving bearing portions 69 formed onthe block element. Locking means, such as cotter pins 10, may be secured to the Vends of the bearing portions 69 Afor Vpreventing displacement of the respective levers 68. Simil larly, `the adjusting block member 66 has oper- -atively secured thereto a pair of spacing. levers 13, which are aligned with the'levers68 and are operatively connected thereto throughthe mevdium of a link member 15,which is pivotally connected by means of a pin 16 to thecentral portions of the levers 13v and by means of a pin 11 `to the adjacent portions of levers 68.

As shown in Fig. 1 vthe respectiveVf pairs of vspacing levers 68 and 13 are angular inform, so that when the portions of said levers connected to'rthe block elements 65 and 66 are substantially parallel as illustrated, the outer ends of the two pairs ofr'levers are spaced apart.V Thefspacing levers 68 are pivotally'connected by means of a lpin 88 to the adjacent end of a pull rod-8|, the

opposite end of which is pivotally connected by means ofA a pin 82 to the centerV portion of the brake lever 25. In like manner the -adjacent outer ends of the spacing levers 13 are connected vby means of a pin 84to a pull rod 85, the other end of which is journaled on a pin 86 connected tothe brake lever 38 rintermediate the ends thereof. Y Y. In operation, when fluid under pressure .is sup- ;plied in the usual manner to thepiston chamber I6 for effecting an application of the brakes, the brake cylinder piston|5 is-moved tothe left, as viewedin Fig. 1, against-the pressure of the spring |9,.while the piston rod 22 is moved in the same .direction together withthe. tubular member 26. It-willloe understoodthat the tubular member 20..,is free to slidefthrough vthe. sleeve-member.35,

which -is normallyfmaintained in the position illustrated under the force of the coil spring 39,

As the piston rod 22 is thus forced outwardly it operates the brake lever 25 about the pin 82 as a fulcrum to exert a pulling force of the pull rod 21, while at the same time the pin 82 is carried to the left, as viewed in the drawing, so that a pulling force is also transmitted through the medium of the pull rod 8|, the interlocked spacing levers 68 and 13, and pull rod 85 to the brake 4lever 30, which is thereby turned about the pin 29 for pulling the rod 32 toward the left. The various elements of the brake rigging are thus operated to elTect application of the brakes.

It will be understood that while the brake lever 25, pull rods 8| and 85, and brake lever 30 are thus subjected to operating forces, the spacing levers 68 and 13 are free to move about the pivotal connections jwith the adjusting block membersr65 and 66 and with the pins 11 and 16 to compensate for relative displacement of the other brake rigging elements, although the -distance separating the pins and 84 is maintained substantially constant. 'c l f.

If the slack inthe ybrake rigging. is not excessive, the application of thebrakes as, just explained will be effected before .the Vpiston l5, has been moved far enough to Vvcause engagement ofthe collar portion 42 thereof with the end .ofthe sleeve member 35. Itheb'rake shoes associated with the brake equipment shown in thev drawing have become .worm-howeven'so `that the brake rigging elements must bemoved to, agreater than normal extent to take.i up the slackthe piston |5 is then moved ',agaifnstthe, pressureof the spring I9 to bringthejcollar portion 42', nto engagement with the sleeve 'member 'for "shifting the sleeve member to the left-,a'gainsltfheforce of the spring 39. Asthejsleevelmember 35 is 'thus shifted from itsY normal position, the, pawl 48 is carried over one or. more'of theIteeth of the ratchet wheel 46, which is meanwhile` held against counterclockwise rotation vby the pawl 5|.

When fluid under pressure Vis 'subsequently 4released from-the piston chamber I6 .ofthebrake cylinder device for eiecting the releaseof the brakes, the spring |9 becomes eiective ,to shift the piston l5 toward lrelease position Ain the usual manner, while the spring-v3g9 at the same time becomes effective to'move the" sleeve member 35 toward thev normal position as illustrated in Fig. 1. As the sleeve member35'is thus shifted to the right under the force of thespring 39, the

pawl 48 acts through the medium of the-ratchet wheel 46 to rotate the shaft 45 .and worm gear portion 56 thereof in1a clockwisedirection as viewed in Fig. 1, thereby 'turning the shaft 58 through the medium of the worm gear vportion 51. The shaft 58 and the screw member 66 mounted thereon are thus rotated in av clockwise direction, as viewed in Fig. 2, for drawingthe adjusting block element 65 toward the left along the screw thread 6| ,(see Fig. 1), while simultaneously effecting movement of the adjusting block member 66 toward the right along the screw thread 62. As the adjusting block members 65 and 66 are thus separated, the spacing levers 68 Iand 13 are turned about the respective pivot pins v11and 16 for drawing the o uter ends of the levers closer together. It will be apparent that with the distance between the pins 8|) and84 thusshortened, the slack in the brake rigging fis .consequently reduced. u From the foregoing it will bes'een thata comemanen brake cylinder andnsiack adjuster cnstructed and arranged accordingfto my. invention may be employed with any existing vehicle brake rigging, and is particularly adaptable for use on a modern railway truck having a minimum of space available for a braking apparatus.

Although a preferred embodiment of the invention has been illustrated and described, it is not intended to limit the scope of the invention to that embodiment or otherwise than by the terms of the appended claims.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. A combination brake cylinder and slack adjuster for a fluid pressure operated brake rigging, comprising a casing, a piston mounted therein and operatively connected to the brake rigging, a movable member mounted within said casing and operable by said piston upon excessive travel thereof, a spring for biasing said member toward a normal position and opposing displacement thereof by the piston, a ratchet mechanism mounted in said casing and operative on movement of said member by said spring, a longitudinally disposed shaft having one end journaled in said casing and geared to said ratchet and pawl mechanism and the other end extending outwardly of said casing, and lever means mounted in screw-threaded connection with said shaft and operative thereby for taking up slack in the brake rigging.

2. A combination brake cylinderand slack adjuster for a fluid pressure operated brake rigging, comprising a casing, a piston and piston `rod mounted therein and operatively connected to the brake rigging, a longitudinally disposed sleeve member surrounding said piston rod and operatively aligned with said piston, a coil spring urging said sleeve member toward a normal position, ratchet and pawl means mounted within said casing and constructed and arranged for operation by said sleeve member under the force of said spring, a longitudinally disposed shaft having one end journaled in said casing and geared to said ratchet and pawl mechanism and the other end extending outwardly of said casing, and lever means mounted in screw-threaded connection with said shaft and operative thereby for taking up slack in the brake rigging.

3. A combination brake cylinder and slack acljuster for a fluid pressure operated brake rigging, comprising a hollow casing structure having an interior annular shoulder, a fluid pressure actuated piston mounted in said casing structure, a release spring interposed between said piston and said annular shoulder, a sleeve member slidably mounted within said annular shoulder and disposed in operative alignment with said piston, a coil spring for urging said sleeve member toward a normal position and for resisting displacement thereof by said piston, a piston rod operatively connecting said piston with the brake rigging, said piston rod being disposed longitudinally within said sleeve member, a ratchet and screw mechanism journaled in said casing structure and operative to take up slack in the brake rigging, and means carried by said sleeve member for actuating said ratchet and screw mechanism when the sleeve member is operated under the force of said coil spring.

4. In a vehicle brake equipment, in combination, a brake cylinder casing structure, a piston and piston rod operatively mounted therein, a iloating brake cylinder lever pivotally connected to said piston rod and operative to apply the brakes, a dead brake cylinder lever pivotally connected to said casing structure and operative to apply the brakes, an adjustable connecting rod assembly operatively connecting said dead brake cylinder lever and said floating brake cylinder lever for rendering said levers cooperative in effecting application of the brakes, and slack takeup mechanism operatively mounted in said casing structureand constructed and arranged for operation by said piston upon excessive travel thereof to effect compensating adjustment of said connecting rod assembly. 5. In a brake equipment for a railway truck, in combination, a casing structure including a brake cylinder portion and a slack adjuster portion, -a brake cylinder piston mounted in said brake cylinder portion, a slack adjuster mechanism.' mounted in said slack adjuster portion and operative by said piston upon excessive travel thereof, a screw-threaded shaft rotatable by said mechanism and projecting outwardly of said casing structure, a live brake cylinder lever operatively connected to said brake cylinder piston, a dead brake cylinder lever pivotally connected to said casing structure, spaced tie rods pivotally connected to the respective live and dead levers intermediate the ends thereof, and a pair of centrally pivoted spacing levers having their inner ends operatively connected to said screwthreaded shaft and their outer ends pivotally connected to said tie rods, respectively.

6. A combination brake cylinder and slackv adjuster for a fluid pressure operated brake rigging, comprising a casing, a piston mounted therein and operatively connected to the brake rigging, a movable member mounted within said casing and operable by said piston upon excessive travel thereof, a spring for biasing said member toward a normal position and opposing displacement thereof by the piston, a ratchet mechanism mounted in said casing and operative on movement of said member by said spring, a rotary shaft disposed longitudinally of and closely adjacent an outer wall of said casing, said shaft having one end journaled in a portion of said casing and geared to said ratchet mechanism, and lever means mounted in screw-threaded connection with said shaft and operative thereby for taking up slack in the brake rigging.

'7. In a vehicle brake system of the type having a live lever and a dead lever forming a part of the brake' rigging in the system and a brake cylinder having a piston therein connected tov one of said levers, in combination, adjustable means interconnecting said live and dead levers for operating one with the other and being adjustable to take up the slack in the brake rigging connected to the levers, and means disposed in the brake cylinder and mechanically actuated by the piston in said brake cylinder for controlling said adjustable means.

8. In a vehicle brake system of the type having alive lever and a dead lever forming a part of the brake rigging in the system and a brake cylinder having a piston therein connected to one of said levers, in combination, adjustable means interconnecting said live and dead levers for operating one with the other and being adjustable to take up the slack in the brake rigging connected to the levers, and means engageable by the piston upon excessive movement thereof due to slack in the brake rigging for operating said adjustable means.

CLYDE C. FARMER. 

